Description

MESH_ANALYZE 3D surface mesh analysis and feature recognition.

[ IND_FG, IND_EG, H_PLOT ] = MESH_ANALYZE( P, F, N, TOL_TH, TOL_AR, TOL_CO, OPT, I_PLOT, H_AX ) Perform analysis and feature recognition on the STL surface mesh data given by the vertex coordinates in P (n_p x 3), faces F (n_f x 3), and outward directed normal vectors N (n_f x 3).

TOL_TH is an optional vector with four entries specifying the following angles (in degrees); dihedral angle cutoff to classify sharp features (default 30), angles to classify needle and cap facets for identifying non-sharp features (default 10 and 160), and maximum edge deviation for growing unconnected feature edges (default 20).

TOL_AR optionally specifies various facet related aspect ratio related tolerances for non-sharp feature identification, namely; Minimum facet height to length (hl-)ratios (default 3), max to min height-ratio (default 2.5) for keeping non-sharp features related to cap edges, as well as hl-ratio for eliminating single unconnected edges (default 1.2).

Coalescence/merging of small surface patches with less than TOL_CO(1) facets (default 2) and maximum edge TOL_CO(2) angle deviation (default 30 degrees) is also optionally performed.

The additional flags in OPT are SHARP and EXTEND. SHARP toggles splitting of sharp (>100 degrees) edges which helps avoid complex shaped patches. SHARP=2 (default) adds all potential edges around the sharp angled vertex, and SHARP=1 only adds the edge with least angle deviation. The flag EXTEND toggles extending/growing of disconnected edges (default true).

The parameter I_PLOT enables plot generation, 1 for surface/boundary plot, and 2 for edge feature plot. An axis handle H_AX can optionally be give.

Output arguments are the facet and edge groupings in IND_FG and IND_EG (corresponding to edges computed with GRIDBDRE, and where IND_EG is zero for internal facet edges). And H_PLOT contains any graphics handles.

See also: mesh_repair, gridbdre